US20100208666A1 - Control channelsin communication network systems - Google Patents
Control channelsin communication network systems Download PDFInfo
- Publication number
- US20100208666A1 US20100208666A1 US12/451,350 US45135008A US2010208666A1 US 20100208666 A1 US20100208666 A1 US 20100208666A1 US 45135008 A US45135008 A US 45135008A US 2010208666 A1 US2010208666 A1 US 2010208666A1
- Authority
- US
- United States
- Prior art keywords
- control channels
- tree structure
- control channel
- nodes
- lower level
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
- H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
- H04B7/2628—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA]
- H04B7/2637—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] for logical channel control
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
- H04L1/001—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding applied to control information
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
- H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/02—Power saving arrangements
- H04W52/0209—Power saving arrangements in terminal devices
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/20—Control channels or signalling for resource management
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/20—Control channels or signalling for resource management
- H04W72/23—Control channels or signalling for resource management in the downlink direction of a wireless link, i.e. towards a terminal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Definitions
- the method described below relates to control channels in communication network systems, and in particular to control channel allocation and decoding e.g. in 3GPP (3 rd Generation Partnership Project) LTE (Long Term Evolution) network systems.
- 3GPP 3 rd Generation Partnership Project
- LTE Long Term Evolution
- LTE technology defines a packet radio system, where all channel allocations are expected to happen in short periods of sub-frames. This is contrary to the older 3G systems, where dedicated signalling channels are necessary to be set up even for packet traffic. It is also different from WLAN (Wireless Local Area Network) type of allocations, where each IP (Internet Protocol) packet transmission contains a transport header.
- WLAN Wireless Local Area Network
- All allocations are signalled in Shared Control Channels, which are present in first multi-carrier symbols of a sub-frame preceding multi-carrier symbols of data channels.
- the control channels are separately coded. That is, a downlink (or uplink) channel is divided into two separate parts, one for control and one for data.
- the data part (PDSCH) carries downlink (or uplink) data for simultaneously scheduled users, while the control part (PDCCH) carries (among others) allocation information for the scheduled users.
- the methods and devices described below are for reducing control channel decoding complexity.
- the method may be implemented as a computer program product.
- a tree search for aggregated control channels is reduced in a systematic way, which will obtain a significant reduction of the number of decoding attempts at a UE (User Equipment) side, while still maintaining most of the scheduling flexibility in an eNB (evolved Node B), i.e. system spectral efficiency versus UE complexity trade-off is obtained.
- UE User Equipment
- eNB evolved Node B
- the UE utilizes the tree structure to reduce the decoding complexity in order to save power. According to an embodiment, power consumption in the decoding/detection of an L1/L2 control channel can be reduced.
- the method is not limited to LTE network systems, but can be applied to any other communication systems requiring dynamic and fast channel allocation, including systems where there will be multiple code rates for the control channel.
- FIG. 1 is an example of a tree structure with three allocated nodes in different levels of the tree.
- FIG. 2 is a data structure diagram of the three allocated nodes of FIG. 1 mapped to sub-carrier resources in a distributed manner.
- FIG. 3 is a matrix diagram illustrating a combination of control channel elements to create aggregated control channel candidates.
- FIG. 4 is a data structure diagram of an example illustrating reduction of possible aggregation options for control channel candidates according to an embodiment.
- FIG. 5 is a schematic block diagram illustrating functions of a user equipment and a network device according to an embodiment.
- a Physical Downlink Shared Control Channel which carries (among others) allocation information for simultaneously scheduled users of a communication network system is arranged to a tree structure having of multiple control channel elements as shown in FIG. 1 .
- a UE User Equipment
- a UE User Equipment
- Each code block is called a control channel candidate as it potentially carries information for one MAC (Medium Access Control) ID.
- the MAC ID is used by the UE or by a group of UEs to detect the channel.
- each node represents a single control channel of a code block.
- the system bandwidth of a given number of sub-carrier resources may be divided to an integer multiple of the largest control channels.
- a given node of the tree i.e., a set of sub-carriers, can be one control channel of the largest code block, of up to two control channels of the second largest code blocks or up to four control channels of the smallest code blocks.
- Each control channel extends entirely over the first n OFDM symbols, which are available for the control channels.
- the control channels may be distributed to the sub-carriers over the system bandwidth to maximize the frequency diversity. For example, there are 4 distributed sets of sub-carrier resources allocated per each code-block. This is illustrated in FIG. 2 .
- FIG. 1 three allocated nodes CB 1 , CB 2 , CB 3 in different levels of the tree structure are shown.
- FIG. 2 shows the three allocated nodes CB 1 , CB 2 , CB 3 mapped to the sub-carrier resources in a distributed manner. It should be noted that these mappings are only examples, and that the mapping in general should provide frequency diversity by scattering over the system bandwidth.
- each control channel has to be uniquely identified by a MAC ID, it can be combined to CRC (Cyclic Redundancy Code) by partly masking CRC bits with the MAC-ID.
- CRC Cyclic Redundancy Code
- the MAC ID is used for addressing both UE specific control channels and common control channels, it is reasonable to define the MAC ID in a compatible way. Thus, reception of any control channel is possible by filtering control channels with the respective MAC ID. Error detection is available from the MAC ID masked CRC.
- the length of the MAC ID is matched to the C-RNTI (Cell Radio Network Temporary Identifier) length.
- a receiver receives symbols of the Downlink Shared Control Channel part of the sub-frame prior to reception and processing of the symbols in the downlink and uplink Shared Data Channels.
- the receiver demodulates and decodes the sub-carriers of the OFDM symbols in which the receiver may search for a set of largest code blocks, e.g. CB 1 of FIG. 1 .
- the Code Block is of known size and the system bandwidth is known, the receiver knows an integer multiple of sub-carrier positions to search for a CB 1 .
- the reception, whether correctly detected or not, may be recognized by Cyclic Redundancy Check detector filtered by a receiver specific c-RNTI identity.
- the receiver knows that the next higher level of tree is masked and not available. For every non-matched CRC check, the UE will continue decoding code blocks (CB 2 ) in the next higher level of the tree searching for a match in two child nodes of the parent node. Further on, for every non-matched CRC check, the UE will continue decoding code blocks (CB 3 ) in the next higher level of the tree searching for a match in two child nodes of the parent node. The search continues until the UE has detected and correctly decoded all control channels, intended for its reception.
- the UE may have to search for common signalling entries by common identifiers.
- the search in the tree may happen in any other order than from the lowest level node towards the higher level nodes.
- the receiver may process the nodes from the highest level of nodes to the lower level of nodes. Further on, the receiver may process the nodes in other arbitrary (or systematic) order based on some measures e.g. SINR (Signal Interference and Noise Ratio) quality of the candidate code block(s).
- SINR Signal Interference and Noise Ratio
- control channel element Aggregation of multiple control channel elements can be used to get larger payloads and/or lower coding rate.
- control channel elements may require a large number of decoding attempts from all the UEs that are listening for a possible allocation.
- An example of a control channel aggregation is shown in FIG. 3 .
- FIG. 4 shows a kind of flat tree structure arising from FIG. 3 .
- FIG. 4 illustrates potential control channel candidates for different aggregation possibilities (both the white and grey areas).
- CCEs control channel elements
- the 24 control channel elements each may form a control channel.
- two control channel elements may be aggregated to form a control channel
- in aggregation level 4 two control channel elements may be aggregated to form a control channel
- four control channel elements may be aggregated to form a control channel
- aggregation level 8 eight control channel elements may be aggregated to form a control channel.
- the control channel structure shown by the white and grey areas in FIG. 4 is put under limitations, such that only the white aggregated control channel candidates are available for scheduling.
- the number of decoding attempts is reduced to 15 (the grey areas are not decoded in search for a control channel candidate), which corresponds to a reduction by a factor of 3.
- there are four control channel candidates in aggregation level 1 four control channel candidates in aggregation level 2 , four control channel candidates in aggregation level 4 , and three control channel candidates in aggregation level 8 .
- control channels at each layer is not important.
- usage of the smallest control channel on all control channel elements is prohibited, while at the same time the smaller control channels are allowed to be combined to aggregated control channels with better coverage.
- the number of decoding attempts that is needed by each UE can be reduced.
- the limitation of the tree is possible due to the frequency diversity applied for all control channel elements, such that each CCE experiences same or similar channel conditions.
- FIG. 5 shows a schematic block diagram illustrating a user equipment 10 and a network device 20 , such as an eNB, according to an embodiment.
- the user equipment 10 includes a receiving/transmitting section 11 and a decoding section 12 .
- the receiving/transmitting section 11 receives symbols from the network device 20 , which includes a receiving transmitting section 21 transmitting the symbols and an allocation section 22 .
- the allocation section 22 allocates control channels represented by nodes of a tree structure, each of the control channels having at least one control channel element carrying information for a respective identifier used to detect a control channel of the control channels, wherein the allocation is performed by limiting allocation of highest level control channels of the control channels, the highest level control channels being represented by nodes of the tree structure at a highest level of the tree structure. For example, in FIG. 1 the highest level is shown by level 3 . Referring to FIG. 4 , the highest level is represented by aggregation level 1 .
- the allocation section 22 may increase allocation of lower level control channels of the control channels, the lower level control channels being represented by nodes of the tree structure at lower levels of the tree structure.
- the lower levels are shown by levels 2 and 1 .
- the lower levels are represented by aggregation levels 2 , 4 and 8 .
- the receiving/transmitting section 21 may transmit the allocated control channels as symbols to user equipments including the user equipment 10 , by distributing the allocated control channels to sub-carriers over a system bandwidth.
- the higher level control channels may be combined to the lower level control channels.
- smaller control channels are allowed to be combined to aggregated control channels with better coverage.
- the allocation section 22 may increase allocation more the lower the level of the tree structure.
- the searching section 12 of the user equipment 10 searches for a control channel by decoding control channels represented by nodes of a tree structure, by using an identifier such as an MAC ID, CRC or c-RNTI, each of the control channels having at least one control channel element carrying information for a respective identifier used to detect a control channel of the control channels, wherein the searching section 12 limits the searching for highest level control channels of the control channels, the highest level control channels being represented by nodes of the tree structure at a highest level of the tree structure.
- an identifier such as an MAC ID, CRC or c-RNTI
- the searching section 12 may increase the searching for lower level control channels of the control channels, the lower level control channels being represented by nodes of the tree structure at lower levels of the tree structure.
- the receiving/transmitting section 11 may receive the control channels as symbols from the network device 20 .
- the searching section 11 may begin the searching with lowest level control channels represented by nodes of the tree structure at a lowest level of the tree structure.
- the lowest level is shown by level 1 .
- the lowest level is represented by aggregation level 8 .
- the network device 20 and user equipment 10 shown in FIG. 5 may have further functionality for working e.g. as eNodeB and UE.
- the functions of the network device and user equipment relevant for understanding the principles are described using functional blocks as shown in FIG. 5 .
- the arrangement of the functional blocks of the network device and user equipment is not construed to limit the invention, and the functions may be performed by one block or further split into sub-blocks.
- control channels represented by nodes of a tree structure are allocated, each of the control channels having at least one control channel element carrying information for a respective identifier used to detect a control channel of the control channels.
- the allocation is performed by limiting allocation of highest level control channels of the control channels, the highest level control channels being represented by nodes of the tree structure at a highest level of the tree structure.
- a control channel is searched for by decoding the allocated control channels, wherein the searching is limited for the highest level control channels.
- the system also includes permanent or removable storage, such as magnetic and optical discs, RAM, ROM, etc. on which the process and data structures of the present invention can be stored and distributed.
- the processes can also be distributed via, for example, downloading over a network such as the Internet.
- the system can output the results to a display device, printer, readily accessible memory or another computer on a network.
Abstract
Description
- This application is the U.S. national stage of International Application No. PCT/EP2008/055557, filed May 6, 2008 and claims the benefit thereof. The International Application claims the benefits of European Application No. 07107652 filed on May 7, 2007, both applications are incorporated by reference herein in their entirety.
- The method described below relates to control channels in communication network systems, and in particular to control channel allocation and decoding e.g. in 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) network systems.
- LTE technology, for example, defines a packet radio system, where all channel allocations are expected to happen in short periods of sub-frames. This is contrary to the older 3G systems, where dedicated signalling channels are necessary to be set up even for packet traffic. It is also different from WLAN (Wireless Local Area Network) type of allocations, where each IP (Internet Protocol) packet transmission contains a transport header.
- According to LTE technology, all allocations are signalled in Shared Control Channels, which are present in first multi-carrier symbols of a sub-frame preceding multi-carrier symbols of data channels. The control channels are separately coded. That is, a downlink (or uplink) channel is divided into two separate parts, one for control and one for data. The data part (PDSCH) carries downlink (or uplink) data for simultaneously scheduled users, while the control part (PDCCH) carries (among others) allocation information for the scheduled users.
- The methods and devices described below are for reducing control channel decoding complexity. The method may be implemented as a computer program product.
- Accordingly, a tree search for aggregated control channels is reduced in a systematic way, which will obtain a significant reduction of the number of decoding attempts at a UE (User Equipment) side, while still maintaining most of the scheduling flexibility in an eNB (evolved Node B), i.e. system spectral efficiency versus UE complexity trade-off is obtained.
- Accordingly it is assumed that there will not be a large amount of users having the same propagation conditions being scheduled at the same time. The tree reduction is obtained by putting some limitations on the tree structure through specifications.
- The UE utilizes the tree structure to reduce the decoding complexity in order to save power. According to an embodiment, power consumption in the decoding/detection of an L1/L2 control channel can be reduced.
- For the purpose of the methods and devices described herein below, it should be noted that
-
- a user equipment may for example be any device by which a user may access a communication network; this implies mobile as well as non-mobile devices and networks, independent of the technology platform on which they are based;
- a user equipment can act as a client entity or as a server entity, or may even have both functionalities integrated therein;
- methods likely to be implemented as software code portions and being run using a processor at one of the server/client entities are software code independent and can be specified using any known or future developed programming language;
- methods and/or devices likely to be implemented as hardware components at one of the server/client entities are hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS, CMOS, BiCMOS, ECL, TTL, etc, using for example ASIC components or DSP components, as an example;
- generally, any method is suitable to be implemented as software or by hardware without changing the idea of the present invention;
- devices can be implemented as individual devices, but this does not exclude that they are implemented in a distributed fashion throughout the system, as long as the functionality of the device is preserved.
- The method is not limited to LTE network systems, but can be applied to any other communication systems requiring dynamic and fast channel allocation, including systems where there will be multiple code rates for the control channel.
- These and other aspects and advantages will become more apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings of which:
-
FIG. 1 is an example of a tree structure with three allocated nodes in different levels of the tree. -
FIG. 2 is a data structure diagram of the three allocated nodes ofFIG. 1 mapped to sub-carrier resources in a distributed manner. -
FIG. 3 is a matrix diagram illustrating a combination of control channel elements to create aggregated control channel candidates. -
FIG. 4 is a data structure diagram of an example illustrating reduction of possible aggregation options for control channel candidates according to an embodiment. -
FIG. 5 is a schematic block diagram illustrating functions of a user equipment and a network device according to an embodiment. - Reference will now be made in detail to the preferred embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
- A Physical Downlink Shared Control Channel (PDSCCH) which carries (among others) allocation information for simultaneously scheduled users of a communication network system is arranged to a tree structure having of multiple control channel elements as shown in
FIG. 1 . During decoding, a UE (User Equipment) will combine or aggregate the control channel elements to create different code blocks or control channel candidates. Each code block is called a control channel candidate as it potentially carries information for one MAC (Medium Access Control) ID. The MAC ID is used by the UE or by a group of UEs to detect the channel. At each level of the tree, each node represents a single control channel of a code block. The number of the control channels at the lowest level of the tree is determined by the system bandwidth and number of OFDM symbols n available for the largest code blocks, as well as the size of the control channel elements. In the example shown inFIG. 1 , n=3. Any node of the tree, which is not occupied by a control channel in this level, is available for the next level of the tree as two control channels, each of which are half of the size of the control channel at the parent node. - The system bandwidth of a given number of sub-carrier resources may be divided to an integer multiple of the largest control channels. A given node of the tree, i.e., a set of sub-carriers, can be one control channel of the largest code block, of up to two control channels of the second largest code blocks or up to four control channels of the smallest code blocks.
- Each control channel extends entirely over the first n OFDM symbols, which are available for the control channels. The control channels may be distributed to the sub-carriers over the system bandwidth to maximize the frequency diversity. For example, there are 4 distributed sets of sub-carrier resources allocated per each code-block. This is illustrated in
FIG. 2 . - In
FIG. 1 , three allocated nodes CB1, CB2, CB3 in different levels of the tree structure are shown.FIG. 2 shows the three allocated nodes CB1, CB2, CB3 mapped to the sub-carrier resources in a distributed manner. It should be noted that these mappings are only examples, and that the mapping in general should provide frequency diversity by scattering over the system bandwidth. - As each control channel has to be uniquely identified by a MAC ID, it can be combined to CRC (Cyclic Redundancy Code) by partly masking CRC bits with the MAC-ID. As the MAC ID is used for addressing both UE specific control channels and common control channels, it is reasonable to define the MAC ID in a compatible way. Thus, reception of any control channel is possible by filtering control channels with the respective MAC ID. Error detection is available from the MAC ID masked CRC. The length of the MAC ID is matched to the C-RNTI (Cell Radio Network Temporary Identifier) length.
- A receiver, e.g. the UE, receives symbols of the Downlink Shared Control Channel part of the sub-frame prior to reception and processing of the symbols in the downlink and uplink Shared Data Channels. The receiver demodulates and decodes the sub-carriers of the OFDM symbols in which the receiver may search for a set of largest code blocks, e.g. CB1 of
FIG. 1 . As the Code Block is of known size and the system bandwidth is known, the receiver knows an integer multiple of sub-carrier positions to search for a CB1. The reception, whether correctly detected or not, may be recognized by Cyclic Redundancy Check detector filtered by a receiver specific c-RNTI identity. For every match of CRC, to which the c-RNTI of the UE does not match, the receiver knows that the next higher level of tree is masked and not available. For every non-matched CRC check, the UE will continue decoding code blocks (CB2) in the next higher level of the tree searching for a match in two child nodes of the parent node. Further on, for every non-matched CRC check, the UE will continue decoding code blocks (CB3) in the next higher level of the tree searching for a match in two child nodes of the parent node. The search continues until the UE has detected and correctly decoded all control channels, intended for its reception. - In addition to search signalling entries with its own receiver specific c-RNTI, the UE may have to search for common signalling entries by common identifiers.
- The search in the tree may happen in any other order than from the lowest level node towards the higher level nodes. Depending on the applied coding scheme, the receiver may process the nodes from the highest level of nodes to the lower level of nodes. Further on, the receiver may process the nodes in other arbitrary (or systematic) order based on some measures e.g. SINR (Signal Interference and Noise Ratio) quality of the candidate code block(s).
- In the following it is assumed that only a single size of a node (i.e. control channel) at the highest level of the tree structure (
level 3 inFIG. 1 ) is defined for a given bandwidth in a cell. The highest level node is referred to as “control channel element”. Aggregation of multiple control channel elements can be used to get larger payloads and/or lower coding rate. - However, the aggregation of the control channel elements may require a large number of decoding attempts from all the UEs that are listening for a possible allocation. An example of a control channel aggregation is shown in
FIG. 3 . - From
FIG. 3 it can be seen that an aggregation of even a relative low number of control channel elements will result in a rather high number of decoding attempts for the UEs listening for resource allocations, and each UE will listen for downlink allocations as well as uplink allocations. In the example inFIG. 3 , there are 6 control channel elements, while the aggregation using a tree structure as shown inFIG. 1 results in 10 potential control channel candidates. This is suboptimal regarding UE complexity, as a UE will have to decode the full amount of control channel candidates even if some of them are not scheduled. - In the following an embodiment will described in greater detail.
-
FIG. 4 shows a kind of flat tree structure arising fromFIG. 3 .FIG. 4 illustrates potential control channel candidates for different aggregation possibilities (both the white and grey areas). As can be seen fromFIG. 4 , there is a total of 24 control channel elements (CCEs), which by default triggers 45 decoding attempts per link direction (i.e. downlink/uplink) allocation. In other words, inaggregation level 1 the 24 control channel elements each may form a control channel. Inaggregation level 2, two control channel elements may be aggregated to form a control channel, inaggregation level 4, four control channel elements may be aggregated to form a control channel, and inaggregation level 8, eight control channel elements may be aggregated to form a control channel. - According to an embodiment, the control channel structure shown by the white and grey areas in
FIG. 4 is put under limitations, such that only the white aggregated control channel candidates are available for scheduling. With this limitation, the number of decoding attempts is reduced to 15 (the grey areas are not decoded in search for a control channel candidate), which corresponds to a reduction by a factor of 3. In other words, there are four control channel candidates inaggregation level 1, four control channel candidates inaggregation level 2, four control channel candidates inaggregation level 4, and three control channel candidates inaggregation level 8. - With the above limitation put on the tree structure, scheduling flexibility is not reduced that much, based on the following arguments:
-
- If there is a lot of user equipments close to an eNB scheduling the control channels, which user equipments require only
aggregation level 1, the aggregatedlevel 2 elements with reduced power can be used to have more users due to the possibility of doing power balancing; in the example shown inFIG. 4 , 9 favourable conditioned users can be scheduled using this approach. In other words, four control channels inaggregation level 1, two control channels inaggregation level 2, two control channels inaggregation level 4, and one control channel inaggregation level 8 can be scheduled. - If a plurality of scheduled users is present at a cell edge (aggregation level 8), additional users cannot be scheduled anyway due to limited number of available control channel elements.
- As the difference between aggregation layers is a factor of 2 and when using power balancing, to some extent there is flexibility to trade aggregation and power between each other.
- If there is a lot of user equipments close to an eNB scheduling the control channels, which user equipments require only
- It should be noted that although the above description is given for an allocation tree for single link direction, the method is also valid for the case where two trees, for uplink and downlink, respectively, are present.
- Further, it should be noted that the number of possible control channels at each layer is not important.
- According to an embodiment, using an allocation rule, usage of the smallest control channel on all control channel elements is prohibited, while at the same time the smaller control channels are allowed to be combined to aggregated control channels with better coverage.
- With the above approach, the number of decoding attempts that is needed by each UE can be reduced. The limitation of the tree is possible due to the frequency diversity applied for all control channel elements, such that each CCE experiences same or similar channel conditions.
-
FIG. 5 shows a schematic block diagram illustrating auser equipment 10 and anetwork device 20, such as an eNB, according to an embodiment. - The
user equipment 10 includes a receiving/transmittingsection 11 and adecoding section 12. The receiving/transmittingsection 11 receives symbols from thenetwork device 20, which includes areceiving transmitting section 21 transmitting the symbols and anallocation section 22. - The
allocation section 22 allocates control channels represented by nodes of a tree structure, each of the control channels having at least one control channel element carrying information for a respective identifier used to detect a control channel of the control channels, wherein the allocation is performed by limiting allocation of highest level control channels of the control channels, the highest level control channels being represented by nodes of the tree structure at a highest level of the tree structure. For example, inFIG. 1 the highest level is shown bylevel 3. Referring toFIG. 4 , the highest level is represented byaggregation level 1. - The
allocation section 22 may increase allocation of lower level control channels of the control channels, the lower level control channels being represented by nodes of the tree structure at lower levels of the tree structure. For example, inFIG. 1 the lower levels are shown bylevels FIG. 4 , the lower levels are represented byaggregation levels - The receiving/transmitting
section 21 may transmit the allocated control channels as symbols to user equipments including theuser equipment 10, by distributing the allocated control channels to sub-carriers over a system bandwidth. - The higher level control channels may be combined to the lower level control channels. In other words, smaller control channels are allowed to be combined to aggregated control channels with better coverage.
- The
allocation section 22 may increase allocation more the lower the level of the tree structure. - The searching
section 12 of theuser equipment 10 searches for a control channel by decoding control channels represented by nodes of a tree structure, by using an identifier such as an MAC ID, CRC or c-RNTI, each of the control channels having at least one control channel element carrying information for a respective identifier used to detect a control channel of the control channels, wherein the searchingsection 12 limits the searching for highest level control channels of the control channels, the highest level control channels being represented by nodes of the tree structure at a highest level of the tree structure. - The searching
section 12 may increase the searching for lower level control channels of the control channels, the lower level control channels being represented by nodes of the tree structure at lower levels of the tree structure. - The receiving/transmitting
section 11 may receive the control channels as symbols from thenetwork device 20. - The searching
section 11 may begin the searching with lowest level control channels represented by nodes of the tree structure at a lowest level of the tree structure. For example, inFIG. 1 the lowest level is shown bylevel 1. Referring toFIG. 4 , the lowest level is represented byaggregation level 8. - It is to be noted that the
network device 20 anduser equipment 10 shown inFIG. 5 may have further functionality for working e.g. as eNodeB and UE. Here the functions of the network device and user equipment relevant for understanding the principles are described using functional blocks as shown inFIG. 5 . The arrangement of the functional blocks of the network device and user equipment is not construed to limit the invention, and the functions may be performed by one block or further split into sub-blocks. - According to an embodiment, on a transmitting side, control channels represented by nodes of a tree structure are allocated, each of the control channels having at least one control channel element carrying information for a respective identifier used to detect a control channel of the control channels. The allocation is performed by limiting allocation of highest level control channels of the control channels, the highest level control channels being represented by nodes of the tree structure at a highest level of the tree structure. On a receiving side, a control channel is searched for by decoding the allocated control channels, wherein the searching is limited for the highest level control channels.
- The system also includes permanent or removable storage, such as magnetic and optical discs, RAM, ROM, etc. on which the process and data structures of the present invention can be stored and distributed. The processes can also be distributed via, for example, downloading over a network such as the Internet. The system can output the results to a display device, printer, readily accessible memory or another computer on a network.
- It is to be understood that the above description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications and applications may occur to those skilled in the art without departing from the scope of the invention as defined by the appended claims which may include the phrase “at least one of A, B and C” as an alternative expression that means one or more of A, B and C may be used, contrary to the holding in Superguide v. DIRECTV, 358 F3d 870, 69 USPQ2d 1865 (Fed. Cir. 2004).
Claims (22)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP07107652 | 2007-05-07 | ||
EP07107652.5 | 2007-05-07 | ||
EP07107652.5A EP1990926B1 (en) | 2007-05-07 | 2007-05-07 | Control channels in communication network systems |
PCT/EP2008/055557 WO2008135575A1 (en) | 2007-05-07 | 2008-05-06 | Control channels in communication network systems |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2008/055557 A-371-Of-International WO2008135575A1 (en) | 2007-05-07 | 2008-05-06 | Control channels in communication network systems |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/050,011 Continuation US9877277B2 (en) | 2007-05-07 | 2016-02-22 | Searching for control channels in a wireless network |
Publications (2)
Publication Number | Publication Date |
---|---|
US20100208666A1 true US20100208666A1 (en) | 2010-08-19 |
US9271266B2 US9271266B2 (en) | 2016-02-23 |
Family
ID=38626484
Family Applications (6)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/451,350 Active 2030-10-21 US9271266B2 (en) | 2007-05-07 | 2008-05-06 | Searching for control channels in a wireless network |
US15/050,011 Active 2028-09-29 US9877277B2 (en) | 2007-05-07 | 2016-02-22 | Searching for control channels in a wireless network |
US15/876,917 Active US10716063B2 (en) | 2007-05-07 | 2018-01-22 | Searching for control channels in a wireless network |
US16/928,749 Active 2028-08-01 US11388664B2 (en) | 2007-05-07 | 2020-07-14 | Searching for control channels in a wireless network |
US17/862,925 Active US11647458B2 (en) | 2007-05-07 | 2022-07-12 | Searching for control channels in a wireless network |
US18/144,710 Pending US20230276356A1 (en) | 2007-05-07 | 2023-05-08 | Searching for control channels in a wireless network |
Family Applications After (5)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/050,011 Active 2028-09-29 US9877277B2 (en) | 2007-05-07 | 2016-02-22 | Searching for control channels in a wireless network |
US15/876,917 Active US10716063B2 (en) | 2007-05-07 | 2018-01-22 | Searching for control channels in a wireless network |
US16/928,749 Active 2028-08-01 US11388664B2 (en) | 2007-05-07 | 2020-07-14 | Searching for control channels in a wireless network |
US17/862,925 Active US11647458B2 (en) | 2007-05-07 | 2022-07-12 | Searching for control channels in a wireless network |
US18/144,710 Pending US20230276356A1 (en) | 2007-05-07 | 2023-05-08 | Searching for control channels in a wireless network |
Country Status (17)
Country | Link |
---|---|
US (6) | US9271266B2 (en) |
EP (1) | EP1990926B1 (en) |
JP (2) | JP5081296B2 (en) |
KR (1) | KR101126490B1 (en) |
CN (1) | CN101689884B (en) |
AU (1) | AU2008248616B2 (en) |
BR (1) | BRPI0811550B1 (en) |
CA (1) | CA2686144C (en) |
DE (1) | DE602007032340C5 (en) |
DK (1) | DK1990926T3 (en) |
ES (1) | ES2432166T3 (en) |
MX (1) | MX2009012027A (en) |
PL (1) | PL1990926T3 (en) |
RU (1) | RU2493654C2 (en) |
UA (1) | UA99727C2 (en) |
WO (1) | WO2008135575A1 (en) |
ZA (1) | ZA200907747B (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120121023A1 (en) * | 2010-04-14 | 2012-05-17 | Yezdi Antia | System and method for multi-carrier multiplexing |
US20130024577A1 (en) * | 2011-07-22 | 2013-01-24 | Avaya Inc. | System and method for establishing a relationship based on a prior association |
US9455812B2 (en) | 2011-07-28 | 2016-09-27 | Huawei Technologies Co., Ltd. | Methods and apparatuses for receiving and sending control channel |
US20160353312A1 (en) * | 2014-02-11 | 2016-12-01 | Huawei Technologies Co., Ltd. | Channel decoding method and apparatus, and distributed decoder |
US11464031B2 (en) * | 2019-11-18 | 2022-10-04 | The Regents Of The University Of California | Techniques for periodic transmission of communications packets |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9281917B2 (en) | 2007-01-03 | 2016-03-08 | Nokia Technologies Oy | Shared control channel structure |
DE602007032340C5 (en) * | 2007-05-07 | 2022-05-05 | Wireless Future Technologies Inc. | Control channels in communication network systems |
US8238475B2 (en) * | 2007-10-30 | 2012-08-07 | Qualcomm Incorporated | Methods and systems for PDCCH blind decoding in mobile communications |
WO2009098568A2 (en) * | 2008-02-04 | 2009-08-13 | Nokia Corporation | Method of creating preferred cce pairs from interleaved mini- cces to create aggregated control channel elements in 3gpp lte |
CN101895988B (en) * | 2009-05-22 | 2013-06-05 | 中兴通讯股份有限公司 | Control channel resource allocation method and device |
WO2011000440A1 (en) * | 2009-07-03 | 2011-01-06 | Nokia Siemens Networks Oy | Extension of physical downlink control channel coverage |
EP2296408A1 (en) * | 2009-09-14 | 2011-03-16 | Alcatel Lucent | A method for scheduling transmissions between a base station and user terminals, a base station and a communication network therefor |
JP5801093B2 (en) * | 2011-04-27 | 2015-10-28 | シャープ株式会社 | Base station, terminal, communication system and communication method |
JP6476306B2 (en) | 2015-01-29 | 2019-02-27 | テレフオンアクチーボラゲット エルエム エリクソン(パブル) | PDCCH initialization suitable for MTC devices |
US10812295B2 (en) * | 2017-11-17 | 2020-10-20 | Qualcomm Incorporated | Search space set hashing under channel estimation capability |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080163002A1 (en) * | 2006-12-29 | 2008-07-03 | Nokia Corporation | Blind estimation of control channel |
US20080159323A1 (en) * | 2007-01-03 | 2008-07-03 | Nokia Corporation | Shared control channel structure |
US20080188247A1 (en) * | 2007-02-02 | 2008-08-07 | Ipwireless, Inc. | Hierarchical organization of paging groups |
US20090325585A1 (en) * | 2007-05-02 | 2009-12-31 | Qualcomm Incorporated | Flexible signaling of resources on a control channel |
US20100067445A1 (en) * | 2007-01-04 | 2010-03-18 | Rinne Mika P | Apparatus, Methods and Computer Program Products Providing a Common Signaling Entry for a Modular Control Channel Structure |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2094409C (en) * | 1992-06-18 | 1998-07-14 | Joshua Seth Auerbach | Multicast communication tree creation and control method and apparatus |
DE19835643C2 (en) * | 1998-08-06 | 2000-05-31 | Siemens Ag | Method and device for channel allocation in a communication system with CDMA subscriber separation |
BR0006905A (en) | 1999-07-10 | 2001-10-30 | Samsung Electronics Co Ltd | Apparatus and method for designating a common channel for dedicated communication in a mobile communication system |
US7321576B2 (en) | 2001-11-15 | 2008-01-22 | Nokia Corporation | Method for compact representation of multi-code signaling in communication systems |
KR100426193B1 (en) | 2001-11-20 | 2004-04-06 | 엘지전자 주식회사 | Plasma Display Panel |
KR100889865B1 (en) * | 2002-11-07 | 2009-03-24 | 엘지전자 주식회사 | Communication method in a mobile radio communication system |
US7016319B2 (en) | 2003-03-24 | 2006-03-21 | Motorola, Inc. | Method and apparatus for reducing co-channel interference in a communication system |
KR101025114B1 (en) | 2003-06-26 | 2011-03-25 | 텔레폰악티에볼라겟엘엠에릭슨(펍) | Method and arrangement in a communication system |
US10355825B2 (en) | 2004-07-21 | 2019-07-16 | Qualcomm Incorporated | Shared signaling channel for a communication system |
US9036538B2 (en) | 2005-04-19 | 2015-05-19 | Qualcomm Incorporated | Frequency hopping design for single carrier FDMA systems |
US9144060B2 (en) | 2005-10-27 | 2015-09-22 | Qualcomm Incorporated | Resource allocation for shared signaling channels |
CN101390356B (en) * | 2006-02-24 | 2013-07-10 | 华为技术有限公司 | Method and apparatus for wireless resource allocation |
KR101468490B1 (en) | 2007-05-02 | 2014-12-10 | 삼성전자주식회사 | Method and apparatus for transmitting/receiving control channels by restricting set of the control channels in wireless telecommunication system |
DE602007032340C5 (en) * | 2007-05-07 | 2022-05-05 | Wireless Future Technologies Inc. | Control channels in communication network systems |
-
2007
- 2007-05-07 DE DE602007032340.1A patent/DE602007032340C5/en active Active
- 2007-05-07 DK DK07107652.5T patent/DK1990926T3/en active
- 2007-05-07 EP EP07107652.5A patent/EP1990926B1/en active Active
- 2007-05-07 ES ES07107652T patent/ES2432166T3/en active Active
- 2007-05-07 PL PL07107652T patent/PL1990926T3/en unknown
-
2008
- 2008-05-06 BR BRPI0811550A patent/BRPI0811550B1/en active IP Right Grant
- 2008-05-06 CA CA2686144A patent/CA2686144C/en active Active
- 2008-05-06 AU AU2008248616A patent/AU2008248616B2/en active Active
- 2008-05-06 UA UAA200912615A patent/UA99727C2/en unknown
- 2008-05-06 WO PCT/EP2008/055557 patent/WO2008135575A1/en active Application Filing
- 2008-05-06 US US12/451,350 patent/US9271266B2/en active Active
- 2008-05-06 JP JP2010506918A patent/JP5081296B2/en active Active
- 2008-05-06 MX MX2009012027A patent/MX2009012027A/en active IP Right Grant
- 2008-05-06 KR KR1020097025561A patent/KR101126490B1/en active IP Right Grant
- 2008-05-06 RU RU2009145117/07A patent/RU2493654C2/en active
- 2008-05-06 CN CN2008800227075A patent/CN101689884B/en active Active
-
2009
- 2009-11-04 ZA ZA200907747A patent/ZA200907747B/en unknown
-
2012
- 2012-08-31 JP JP2012192230A patent/JP5355765B2/en active Active
-
2016
- 2016-02-22 US US15/050,011 patent/US9877277B2/en active Active
-
2018
- 2018-01-22 US US15/876,917 patent/US10716063B2/en active Active
-
2020
- 2020-07-14 US US16/928,749 patent/US11388664B2/en active Active
-
2022
- 2022-07-12 US US17/862,925 patent/US11647458B2/en active Active
-
2023
- 2023-05-08 US US18/144,710 patent/US20230276356A1/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080163002A1 (en) * | 2006-12-29 | 2008-07-03 | Nokia Corporation | Blind estimation of control channel |
US20080159323A1 (en) * | 2007-01-03 | 2008-07-03 | Nokia Corporation | Shared control channel structure |
US20100067445A1 (en) * | 2007-01-04 | 2010-03-18 | Rinne Mika P | Apparatus, Methods and Computer Program Products Providing a Common Signaling Entry for a Modular Control Channel Structure |
US20080188247A1 (en) * | 2007-02-02 | 2008-08-07 | Ipwireless, Inc. | Hierarchical organization of paging groups |
US20090325585A1 (en) * | 2007-05-02 | 2009-12-31 | Qualcomm Incorporated | Flexible signaling of resources on a control channel |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120121023A1 (en) * | 2010-04-14 | 2012-05-17 | Yezdi Antia | System and method for multi-carrier multiplexing |
US9264675B2 (en) * | 2010-04-14 | 2016-02-16 | Hughes Network Systems, Llc | System and method for multi-carrier multiplexing |
US20130024577A1 (en) * | 2011-07-22 | 2013-01-24 | Avaya Inc. | System and method for establishing a relationship based on a prior association |
US9324057B2 (en) * | 2011-07-22 | 2016-04-26 | Avaya Inc. | System and method for establishing a relationship based on a prior association |
US9455812B2 (en) | 2011-07-28 | 2016-09-27 | Huawei Technologies Co., Ltd. | Methods and apparatuses for receiving and sending control channel |
US10148403B2 (en) | 2011-07-28 | 2018-12-04 | Huawei Technologies Co., Ltd. | Methods and apparatuses for receiving and sending control channel |
US10805053B2 (en) | 2011-07-28 | 2020-10-13 | Huawei Technologies Co., Ltd. | Methods and apparatuses for receiving and sending control channel |
US20160353312A1 (en) * | 2014-02-11 | 2016-12-01 | Huawei Technologies Co., Ltd. | Channel decoding method and apparatus, and distributed decoder |
US10285086B2 (en) * | 2014-02-11 | 2019-05-07 | Huawei Technologies Co., Ltd. | Channel decoding method and apparatus, and distributed decoder |
US11464031B2 (en) * | 2019-11-18 | 2022-10-04 | The Regents Of The University Of California | Techniques for periodic transmission of communications packets |
US11856596B2 (en) | 2019-11-18 | 2023-12-26 | The Regents Of The University Of California | Techniques for periodic transmission of communications packets |
Also Published As
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11647458B2 (en) | Searching for control channels in a wireless network | |
US11758569B2 (en) | Apparatus and method of resource allocation for data and control channels in a wireless communication system | |
TWI669013B (en) | Methods of efficient downlink control information transmission and user equipment thereof | |
US9681436B2 (en) | Method for search space configuration of enhanced physical downlink control channel | |
US9883526B2 (en) | Physical structure and reference signal utilization of enhanced physical downlink control channel for OFDM/OFDMA systems | |
US8873489B2 (en) | Signaling methods for UE-specific dynamic downlink scheduler in OFDMA systems | |
JP6100888B2 (en) | Common mapping of resource elements to enhanced resource element groups | |
US7940795B2 (en) | Signaling limitation of multiple payload sizes for resource assignments | |
KR20150029024A (en) | Control information transmission method, base station, and user equipment |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NOKIA SIEMENS NETWORKS OY, FINLAND Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FREDERIKSEN, FRANK;KOLDING, TROELS EMIL;SIGNING DATES FROM 20091027 TO 20091110;REEL/FRAME:024040/0918 |
|
AS | Assignment |
Owner name: NOKIA SOLUTIONS AND NETWORKS OY, FINLAND Free format text: CHANGE OF NAME;ASSIGNOR:NOKIA SIEMENS NETWORKS OY;REEL/FRAME:033332/0684 Effective date: 20130819 Owner name: WIRELESS FUTURE TECHNOLOGIES INC., CANADA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NOKIA SOLUTIONS AND NETWORKS OY;REEL/FRAME:033325/0189 Effective date: 20140624 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 4 |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 8 |